add Docker Compose configuration for Traefik and MySQL, update environment variables

main.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"log"
 	"net/http"
+	"os"
 	"time"
 
 	"github.com/go-chi/chi/v5"
@@ -23,6 +24,10 @@ func main() {
 	// Load .env (ignored if not present in production)
 	_ = godotenv.Load()
 
+	if name := os.Getenv("INSTANCE_NAME"); name != "" {
+		log.SetPrefix("[" + name + "] ")
+	}
+
 	cfg := config.Load()
 
 	db, err := database.Connect(cfg)